BIGELOW : MEDUSAE FROM THE MALDIVE ISLANDS. 267 
windings of the chymiferous tubes are much less complex, and the muscle 
fibres occupy more nearly the whole substance of the lobes. 
Beroe; sp. 
One young specimen of this genus was taken on January 19, near Guradu 
island, on the surface. It had arrived at nearly mature form, except that the 
rows of vibratile combs extended only about halfway from the apical pole to 
the mouth. The chymiferous tubes were put into communication by an ex- 
tremely simple network similar to that described by Avassiz and Mayer for 
Beroe australis (Bull. Mus. Comp. Zodl., vol. 32, p. 177, plate 16). It may 
be the young of that species. 
Cestus pectenalis, sp. nov. 
Plate 8, Fig. 30. 
A species of Cestus was exceedingly abundant on January 19, on the surface 
near Guradu island, and on examination proved to be a wholly distinct species. 
In general form, as well as in its movements, it closely resembles Cestus veneris, 
but differs from it in the possession of a large and prominent orange spot at 
either end, and in the extent and structure of the ciliary bands. These extend 
from near the apical sense organ along the aboral edge of the band, following 
the chymiferous tube to the extremity of the lobe. They do not extend along 
the oral edge of the lobe, but come to an end at its extremity. The vibratile 
combs are comparatively few in number, and set at considerable distances from 
one another. ‘The cilia are very long and rigid, presenting a comb-like appear- 
ance. The lateral flattening of the animal is excessive. The digestive cavity 
is broad, but short. The longest specimen captured measured one metre, by 
forty mm. in breadth; but the size was very variable. No Cestus with pig- 
ment patches has ever been described, and the comb-like structure of the 
ciliary bands, and their restriction to the aboral edge of the animal, are of even 
vreater Importance. It seems probable that further investigation may prove 
them to be of generic significance. Like Cestus veneris, this species is ex- 
tremely graceful in the water, moving in slow, ribbon-like undulations, and 
shining with brilliant violet iridescence. 
